Circuit breaker



May 9, 1944.

C. E. BAZLEY CIRCUIT BREAKER Filed Sept. 11; 1942 Invenbof: cam E. B ZIQ L His Attgrhgs.

Patented May 9, 1944 CIRCUIT BREAKER Carl E. Bazley, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application September 11, 1942, Serial No. 457,899

5 Claims.

My invention relates to circuit breakers, more particularly to mechanical interlocks for interlocking together two or more electric switches or contactors so that one only can be moved to its closed circuit position at any one time, and has for its object a simple and rugged device which provides for movement of both of the switches to their full open positions at the same time.

In carrying out my invention, I utilize a pivoted cam mounted between two parallel rectilinearly movable members having surfaces cooperating with the cam so that both'members and hence both the switch members when in their open circuit positions are free of the cam, but movement of either one of the members to a closed circuit position moves the cam into looking relation with the other member.

For a more complete understanding of my invention, reference should be had to the accompanying drawing, Fig. 1 of which is an elevation view of interlocking means embodying my invention as applied to two switch members shown diagrammatically; Fig. 2 is a view similar to Fig. 1 showing one of the switch members raised to a closed circuit position; Fig. 3 is a view partly in section taken along the line 33 of Fig. 1 looking in the direction of the arrows; while Fig. 4 is a sectional view taken along the line 4-4 of Fig. 1 looking in the direction of the arrows.

Referring to the drawing, I have shown my invention as applied to the mechanical interlocking of two switches or contactors operated by plunger armatures l9 and II, shown diagrammatically, which are provided respectively with bridging electric contacts l2 and I3. The plungers are operated from their lower and open circuit positions shown to raised positions by means of operating coils l4 and [5. Actually these plungers l0 and II may be the movable armatures of two contactors of the type described and claimed in U. S. Patent 2,064,632, granted on December 15, 1936, to Robert H. Schmitt.

These two plungers are mechanically interlocked together by cam means comprising a heart-shaped cam l6 mounted for movement about a pivot ll secured to a support [8. This support H3 is shown as a metallic plate parallel with the plane of movement of the two parallel plungers It and H. The heart-shaped cam has secured to it at its lower end, as viewed in the drawing, a roller l9. This roller is mounted on a pivot 29 carried on a strap member 2i whose upper end is rigidly secured to the heart cam,

Cooperating with the heart and roller cam mechanism are two plate slider members 22 and 23 mounted on pairs of pins 24 and 25 on the plate [8 for movement in a vertical direction, as viewed in the drawing in paths parallel with each other. As shown, the pins extend through elongated apertures 26 and 21 in the plates whereby the plates have freedom of movement upward with respect to the support 18. Also, the plates have their outer sides bent backward at right angles to form right angle extensions 28 and 29 which are provided with slots 30 and 3t. Into these slots extend respectively the ends of connecting projections or arms 32 and 33' secured to the plungers It and II, In this manner the plungers are mechanically connected to the sliding plates 22 and 23.

For cooperation with the heart cam l6 and roller IS the plates 22 and 23 are provided on their adjacent edges with specially formed curved cam surfaces 34 and 35. These surfaces or edges of the plates 22 and 23 are shaped to correspond with the heart cam and roller so that when one coil is energized its plate cam 22 or 23 pushes the roller aside in moving upward and thereby locks the other plate and plunger against upward movement, Moreover, if both coils are energized at the same time, both of the plate cams engage the roller and consequently both are locked in their lowermost or open circuit positions,

This action will be clear from an examination of Fig. 2 showing the plate cam 23 in its raised position, the coil l5 having been energized. In moving upward the lower end of the cam surface 35 engaged the roller l9 pushing it toward the left and thereby turning both the roller and the heart cam in a clockwise direction about their pivot ii to the position shown in Fig. 2. Thus the roller I9 is moved into the path of the cam suriace 34 on the member 22 and the member 22 is thereby securely locked in its lowermost position, as shown. When the coil I5 is deenergized and the plate member 23 moves downward, its upper cam portion engages the upper end of the heart It and thereby moves the heart back to its upright position, as shown in Fig. 1. However, it is contemplated that the heart and roller are to be freely pivoted on the pivot H with their center of gravity below the pivot so that when released the heart and roller cam means is moved by gravity to its central upright positions shown in Fig. 1.

It will be observed from Fig. 1 that both slider members and 23, and therefore both switch members l2 and 13, can be in their lowermost .positions at the same time, which is a distinct advantage over mechanical interlock means utilizing levers.

It will be noted, as Shown, that each of the cam surfaces 34 and 35 is formed with an upper substantially Straight portion and with a lower curved portion. More specifically, the cam surface 34 is provided with an upper substantially straight portion 34a which cooperates with the heart cam and with a lower curved portion 34b which cooperates with the roller. Moreover, the lower cam surface 34b is shaped in the event it is lifted with the roller in engagement with it, as seen in Fig. 2, to apply a counterclockwise rotation to the heart and cam combination. In other words, this curved surface applies a force to the roller which is along a line passing to the right, as seen in Fig. 2, of the pivot IT. The cam surface 38 is similarly constructed.

Also, the extreme lower end of each cam surface when in its uppermost position engages the roller at a point which is somewhat lower than the pivot 20 of the roller. As seen in Fig. 2, the lower end 36 of the cam surface 35 engages the roller at a point below the pivot of the roller. Therefore, with the parts in the positions shown in Fig. 2, if an upward force is applied to the slider 22, as by energization of the coil ID, the heart roller cam means is forced in a counterclockwise direction against the lower end 36 and the roller tends to move onto the cam surface 35 thereby applying a downward force to the slider 23.

This cooperation is of advantage in the event that the contacts stick or weld together whereby the sticking contacts are forced apart. Thus, as seen in Fig. 2, when the coil I is deenergized if the plunger and slider 23 fail to drop because of welding of the bridging contact I3 with the stationary contacts (not shown) then when the coil I4 is energized, a suflicient downward force will be applied to the slider 23 to break the weld and move the slider 23 and bridging contact to their downward positions.

Furthermore, the heart and roller interlock mechanism effectively prevents movement of both switches to their raised positions at the same time. It will be observed that when the coils l4 and I5 are energized at the same time both sliders 22 and 23 will engage the bottom of the roller l9 and will be prevented from moving to their uppermost positions. Each slider, however, applies a lateral force to the roller tending to move it into locking engagement with the other slider and consequently, if one coil exerts a greater force, its slider may push the roller into locking engagement with the other slider thereby permitting the first slider and switch to move to its raised position.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with two separately movable electric switch members of two operating members mounted for movement with relation to each other, said operating members having sides adjacent each other shaped to form cam surfaces, a mechanical connection between one of said switch members and one of said operating members, a mechanical connection between the other of said switch members and the other of said operating members, and a latch member between said operating members biased to a position to hold said operating members against movement simultaneously in a predetermined direction, said latch member being movable upon movement of either one of said operating members separately to provide for such movement and into locking relation with the other of said cam surfaces.

2. The combination with two electric switch members of a support, two operating members slidably mounted on said support for movement in directions parallel with each other, a mechanical connection between each of said switch members and one of said operating members, said operating members having their adjacent sides shaped toform cam surfaces, and a cam member pivotally mounted on said support between said cam surfaces thereby normally to latch both of said operating members against simultaneous movement but movable by either one of said operating members into locking relation with the other of said operating members and returned by said first operating member to an intermediate position between said operating members.

3. The combination with two electric switch members, of a support, two slider members s1idably mounted on said support for movement in directions parallel with each other, a mechanical connection between each of said slider members and one of said switch members, said sliders having their adjacent sides shaped to form cam surfaces, and a, heart and roller cam mechanism pivotally mounted on said support between said cam surfaces so that when one of said slider members is moved it engages said roller and moves said roller into locking relation with the other of said slider members and said heart cam into the return path of said one slider member, and when said one slider member is returned to its original position it engages said heart cam and thereby moves said heart and roller cam mechanism to an intermediate position between said slider members.

4. The combination with two electric switch members of a support, two slider members slidably mounted on said support for movement substantially vertically in directions parallel with each other, a mechanical connection between each of said slider members and one of said switch members, said slider members having their adjacent sides shaped to form oppositely deposed cam surfaces each having an upper substantially straight portion and a lower curved portion extending toward the other slider member, a heart-shaped cam mechanism pivoted on said support between said straight cam portions with its pointed end uppermost, the pivot for said heart cam mechanism being above the center of gravity of said heart cam mechanism whereby said mechanism assumes a normal position midway between said cam surfaces, said curved cam portions being shaped to apply a lateral force to the lower end of said cam mechanism to move it into locking engagement with the other cam surface and said straight cam portion engaging the upper end of said heart cam mechanism to move it toward said normal position.

5. The combination with two electric switch members of a support, two slider members slidably mounted on said support for movement substantially vertically in directions parallel with positioned below said heart cam, said curved cam surface being shaped to apply a lateral force to said second cam to move it into locking engagement with the other curved cam surface and the lower end of each cam surface when its slider member is in its raised position engaging said second cam at a point such that an upward force applied to the other slider member tends to force said first slider member down- 10 ward.

CARL E. BAZLEY. 

